1. Field of Invention
This invention relates to protecting surfaces against unexpected explosions, and specifically, countering an external explosion with a counter-explosion.
2. Prior Art
Although this invention has wider scope, its original motivation was to provide protection to military vehicles and their occupants from roadside bombs, also known as improvised explosive devices or IEDs. The problem of IEDs first became apparent in Iraq in 2002, when IEDs took the lives of four coalition members; the lethality of these devices has been growing ever since. In 2010, 368 coalition troops were killed by IEDs, and the total for ten years of war in Iraq and Afghanistan is 953. The number of non-lethal casualties is several times larger. [For ease of reference, the term IED will be used throughout this specification, with the understanding that it may refer to any bomb or other explosive device, and such term is not intended to be limiting in any manner.]
In early 2006, an organization called the Joint IED Defeat Organization, or JIEDDO, was formed to deal specifically with the problem of the IED. Thus far, JIEDDO has spent approximately $20 billion in search of a solution, much of it on sponsored research. While JIEDDO has had many successes, solving the IED problem remains a high priority for the military.
The IED problem has been attacked on many fronts. One of the most effective has been improvement in armor, including the development of active armor. Several patents issued to Zank et al., including U.S. Pat. No. 7,424,845, illustrate this technology. Other patents pertaining to ballistic (active) armor include U.S. Pat. No. 4,194,431 issued to Markus et al., and U.S. Pat. Nos. 6,782,793 and 7,114,428 issued to Lloyd. Active armor comprises two layers of armor between which small shaped charges are positioned. When an object strikes the outer layer with significant force, the charges are ignited to provide a counterforce and protect the inner armored layer. The main disadvantages with active armor are the substantial weight added to a vehicle and its increased acquisition and operating costs. The added weight may also render the vehicle less agile and less mission-capable.
Another approach to defeating the IED is to detect the device before it can go off, and then to remove or discharge it. U.S. Pat. No. 7,680,599 issued to Steadman, et al. seeks to detect the actual emplacement of IEDs utilizing sensors that have been pre-installed. A reporting signal is relayed to the base station via other sensors to elicit a response. U.S. Pat. No. 7,717,023, issued to Pereira, et al., “detects the IED . . . [by]: detecting internal battery components; detecting magnetic signature(s) of the IED; detecting a characteristic energy spectrum of the IED; and/or detecting characteristic chemical signatures of the device(s).” However, prior detection has been only partially successful.
IEDs may be set off by a remote signaling device, such as a cell phone Jamming the signaling device has proven to be a successful technique. For example, U.S. Pat. No. 7,870,813 issued to Ham, et al. seeks to jam electromagnetic signals by broadcasting electromagnetic waves over a suspected area. Mine rollers can be used to defeat pressure-sensitive explosive devices. Intelligence is another effective approach. For example, troops seek to gain the confidence of locals whom they hope will disclose the placement of IEDs.
However, no prior art has been found regarding the current invention, which utilizes counter-explosions to defeat the IED. A counter-explosion can offer the power and the quick response time required to attenuate an IED's shockwave and to repel or deflect its shrapnel. Perhaps one way to account for the apparent lack of prior art is to observe that sufficiently fast components for detecting and responding to an IED attack in the short time available have only come onto the market relatively recently.